Handle for exothermic mold with spring connectors

ABSTRACT

Disclosed is a handle clamp for an exothermic mold. The clamp includes a pair of legs, each having a plurality of rods that are shaped to fit into engagement holes on sections of the mold. The rods of each leg engage with one section of the mold. Engagement brackets are rotatably disposed on one or more or the rods. The brackets each have a thumb bolt that can be extended toward a mold section connected with the clamp. When engaged with the mold section, the thumb bolt stabilizes the mold section on the handle. A detent mechanism is provided between the bracket and the leg of the handle. The detent mechanism releaseably holds the bracket in one of a selected plurality of rotational positions with respect to the rod. By selecting different rotational positions for the brackets, the handle can be configured to engage with different configurations of mold. The thumb bolts that are biased toward the mold section by a spring. The bolts include a key that can be aligned or misaligned with a key slot on the bracket. By aligning the key with the key with the key slot, the bolt can be moved toward or away from the mold section under the biasing force of the spring. By misaligning the key and key slot, the bolt can be locked into engagement with the mold section or else held in a disengaged position.

This application claims priority under 35 U.S.C. § 119 to U.S.Provisional Patent Application No. 62/548,004, filed on Aug. 21, 2017,and U.S. Provisional Patent Application No. 62/624,181, filed on Jan.31, 2018. The disclosures of these applications are incorporated hereinby reference.

BACKGROUND Field

The present disclosure relates to handles for assembling and positioningmolds to create exothermic welds. In particular, the present disclosuredescribes a handle that is adjusted to engage with differentconfigurations of exothermic mold components. The present disclosurefurther describes a handle that connects with mold components usingspring-driven connectors

Description of the Related Art

Exothermic molding is a technique for joining metal objects, such aselectrical conductors, using a highly exothermic chemical reaction.Welds created using this technique are mechanically strong and provide asecure, low resistance electrical connection between the objects. Suchwelds may be useful for lightning arrestors, grounding connections forelectrical utility equipment, and the like.

Exothermic welding uses a powdered reaction mixture held in the reactionchamber of a mold. When the mixture is ignited it produces a moltenmetal. The molten metal flows from the reaction chamber into a moldcavity. Objects to be welded are positioned in the mold cavity. Themolten metal wets the objects and fills the mold cavity. When the metalcools and solidifies the mold is removed, leaving the finished moldedjoint. Exothermic welding relies on a chemical reaction, for example,between copper oxide and powdered aluminum, that results in moltencopper. Such reactions can reach temperatures in excess of 4000° F.Molds are typically made of refractory materials, such as ceramic orgraphite, that can withstand these temperatures.

Molds are shaped to allow conductors with varying sizes, shapes, andconfigurations to be positioned in the mold cavity. Once the conductorsare welded together, the mold needs to be removed from around the newlycreated joint. The configuration of conductors may be such that portionsof the mold need to be separated from one another to release theconductors and welded joint from the mold.

One way to provide a mold that can be removed from welded conductors isto use a single shot mold. A single shot mold is formed from aheat-resistant ceramic body with a reaction chamber that holds thereactant mixture and is positioned above a mold cavity that is shaped toform a welded joint. The mixture is ignited and the resultant liquidmetal flows into a cavity surrounding the conductors to create thejoint. The ceramic mold is then broken away, releasing the weldedconductors. Because the single shot molds are broken away once the weldis complete, they can be formed from a single piece of material and donot require separable sections to release the welded conductors. Singleshot molds may be relatively expensive to use since a new mold isrequired each time a weld is made.

SUMMARY

The present disclosure relates to apparatuses and methods to addressthese difficulties.

An alternative to using single shot molds is to use a reusable mold. Areusable mold is formed from separable sections that have faces shapedto form a mold cavity and to hold the conductors in the properconfiguration to form the welded joint. The mold sections are clampedtogether to form a mold cavity around the conductors. A reactant chamberabove the mold cavity is filled with the reactant mixture and ignited,delivering molten metal to the mold cavity to create the weld. When theweld is complete, the mold sections are separated, allowing the moldsections to be removed intact from the welded conductors and reused.

To hold faces of the mold sections together and to position the moldwith respect to conductors, a handle clamp is used. The handle clamp hasrods that fit into holes in the mold sections to apply force to closeand open the mold. The handle clamp has a locking mechanism to hold themold closed while the weld is created. The handle clamp has mountingbrackets fitted to the rods to secure the mold sections onto the rods.The mounting brackets each include a thumb bolt that is threaded throughthe bracket. To secure a mold section to the handle clamp, the installerfits the mold section over the rods and tightens the thumb bolts toengage with stabilizer holes on the mold section.

Molds may be designed with mold sections that separate from one anotheralong a plane, for example, along a horizontal or vertical plane. Thehandle clamp is adjusted to accommodate different mold designs byrotating the mounting brackets about the rods so that the thumb boltsengage with the correct surface of the mold sections and so that thebrackets do not interfere with the insertion of the rods into the moldsections.

Adjusting a handle clamp and connecting it with different configurationsof mold may be cumbersome, particularly when the mold is used to createmultiple welds and may be hot as a result of a previous moldingoperation. Because mounting bracket can rotate with respect to the rods,the brackets may inadvertently interfere with insertion of the rods intothe mold sections. The installer may have to hold the brackets in placewhile at the same time inserting the rods into the mold sections toassure that the rods are fully inserted into the mold sections. Inaddition, to make sure the thumb bolts properly engage with stabilizerholes on the mold, the installer must hold the brackets in the correctposition while turning the thumb bolts.

One aspect of the disclosure describes a handle clamp for an exothermicmold that includes mounting brackets that can be removably fixed intoselected orientations. This allows the installer to set theconfiguration of the handle to accommodate a selected type of mold sothat the rods can be fully inserted into the mold without having tomanually hold the brackets in place. This also simplifies the task oftightening the thumb bolts to engage with mold sections because theselected positions of the brackets assure proper alignment of the thumbbolts with stabilizer holes.

According to another aspect of the disclosure, brackets are providedwith a detent mechanism that fixes the bracket in either a parallel orperpendicular orientation with respect to the handle. The bracket has aplurality of holes on the surface facing the handle. The handle has apost or convex portion extending toward the bracket. The locations ofthe holes on the bracket are selected so that engagement of a selectedhole with the post fixes the bracket into one of a plurality of thedesired angular positions about the rod. A spring presses the brackettoward the surface of the handle, keeping the hole and post engaged withone another and holding the bracket in the selected angular position.Before connecting a selected exothermic mold with the handle, aninstaller puts the brackets in the proper positions to hold the sectionsof the selected mold. The rods are inserted into corresponding holes onthe mold. When the rods are fully inserted into the mold, the bracketsalign with stabilizer holes on the mold. The installer fixes the mold tothe handle by tightening the thumb bolts to engage the stabilizer holes.

When another configuration of mold is required, the installer adjustsone or more of the brackets so that a different hole on the bracketengages with the post on the handle clamp. The detent arrangement holdsthe bracket in the newly selected position while the installer fits thenew mold sections over the rods and tightens the thumb bolts to fix thehandle clamp with the new mold.

According to a further aspect of the disclosure, instead of thumb bolts,a handle clamp is disclosed that includes spring-driven bolts thatengage with stabilizer holes on the mold sections. One or more bracketsinclude a hole through which the bolt is inserted. A retaining ring isaffixed to the bolt and a coil spring is disposed between the retainingring and a distal surface of the bracket. The spring provides a biasingforce that drives the bolt toward a mold section fitted to the handle.The distal end of the bolt engages a stabilizer hole on the mold sectionpreventing the mold section from disengaging from the handle.

The bolt includes one or more protrusions or keys extending radiallyoutward from the surface of the bolt. The hole in the bracket includes aslot through which the protrusion or key can fit, provided the bolt isangularly oriented so the protrusion or key is aligned with the slot. Todisengage a mold section from the handle, an installer rotates the boltuntil the protrusion or key aligns with the slot and pulls the bolt inthe proximal direction until the protrusion or key is proximal of thebracket. The installer rotates the bolt so the protrusion or key is nolonger aligned with the slot and releases the bolt, which moves distallyunder the bias force exerted by the spring. This brings the protrusionor key in contact with the proximal surface of the bracket, securelyholding the distal tip of the bolt away from the mold section so that itdoes not interfere with the installation of a new mold section. Toengage a new mold section with the handle, the installer rotates thebolt so that the key or protrusion aligns with the slot, allowing thebolt to move toward the mold section under the biasing force of thespring. The tip of the bolt engages with the corresponding stabilizerhole on the mold section. The installer then rotates the bolt so thatthe key or protrusion no longer aligns with the slot and the proximalend of the key or protrusion contacts the distal surface of the bracket,preventing the bolt from moving away from the mold section and assuringthat the engagement of the bolt in the mounting hole is secure.

According to a further aspect of the disclosure there is provided ahandle clamp for an exothermic mold comprising a pair of grips, a pairof legs connected with respective ones of the grips, the legs arrangedto move toward and away from one another in response to motion of thegrips. a plurality of engagement rods disposed on each of the legs,wherein the engagement rods on each leg are adapted to engage withrespective sections of an exothermic mold, one or more brackets, eachbracket rotatably disposed on one of the rods, and a detent mechanism toreleasably hold the bracket in a selected angular position with respectto the rod.

According to a further aspect of the disclosure the detent mechanismcomprises a convex feature and a plurality of concave features arrangedradially about the engagement rod, the convex feature disposed on theleg or the bracket and the concave features disposed on the other of theleg or the bracket, the concave and convex features shaped to engagewith one another and positioned so that when a selected one of theconcave features is engaged with the convex feature, the bracket ispositioned in a respective one of a plurality of angular positions aboutthe rod. The detent mechanism further comprises a force applying memberadapted to apply a force to hold the engaged convex and concave featuresagainst one another. The force applying member is one of a coil spring,a spring washer, an elastomeric washer, and a magnetic insert.

According to a further aspect of the disclosure the concave feature is ahole or dimple on the leg or bracket. According to a further aspect ofthe disclosure the convex feature is a pin extending from one of the legor bracket and the concave feature is a hole in the other of the leg orbracket.

According to a further aspect of the disclosure the handle clamp furthercomprises a locking mechanism, the locking mechanism releasably lockingthe grips in a closed position.

According to a further aspect of the disclosure the handle clamp furthercomprises a bolt hole through the bracket and a bolt disposed in thebolt hole and movable toward and away from a surface of the mold andwherein the bolt and the bolt hole are in threaded engagement with oneanother. The bolt hole further comprises a key slot, wherein the boltfurther comprises a key, wherein the bolt is rotatable in the hole andwherein, when the key is aligned with the key slot, the bolt can slidethrough the bolt hole. According to a further aspect of the disclosure aproximal end of the key engages a distal surface of the bracket when atip of the bolt engages with the mold section. The bolt comprises abolt-driving spring arranged to bias the bolt in a direction toward oraway from the mold, wherein the bolt further comprises a springretaining feature, and wherein the coils spring is disposed between asurface of the bracket and the spring retaining feature.

According to a further aspect of the disclosure the bolt furthercomprises a threaded portion adapted for threaded engagement with athreaded hole of the mold section. According to a further aspect of thedisclosure the threaded portion of the bolt is provided only on aproximal portion of the bolt.

According to a further aspect of the disclosure there is provided amethod for forming a weld comprising the steps of: providing anexothermic mold formed from a plurality of mold sections wherein themold sections comprise rod engaging holes, stabilizer holes, and a moldcavity; providing a handle clamp, the handle clamp comprising: a pair ofgrips, a pair of legs connected with respective ones of the grips, thelegs arranged to move toward and away from one another in response tomotion of the grips, a plurality of engagement rods disposed on each ofthe legs, wherein the engagement rods on each leg are adapted to beinserted into engaging holes of respective sections of the mold, one ormore brackets rotatably disposed on respective ones of the rods, whereinthe bracket comprises a bolt hole, a bolt movably disposed in the bolthole, and a detent mechanism to releasably hold the bracket in aselected angular position with respect to the rod; positioning thebracket in the selected angular position; engaging the detent mechanismto hold the bracket in the selected angular position; fitting theengagement rods into the rod engagement holes of the mold sections;extending the bolt through the bolt hole toward the mold section;engaging a tip of the bolt with a respective stabilizer hole of the moldsection; positioning the mold sections adjacent a structure to bewelded; squeezing the grips to press the mold sections together;activating an exothermic reaction in the mold to form the weld in themold cavity; separating the grips to separate the mold sections; andremoving the weld from the mold cavity.

According to a further aspect of the disclosure the bolt and bolt holecomprise mutually engaged threads and the step of extending comprisesrotating the bolt.

According to a further aspect of the disclosure the handle clamp furthercomprises a spring connected with the bolt and the step of extendingcomprises biasing the bolt into engagement with the mold section with abiasing force applied by the spring. The bolt further comprises a key,the bolt hole further comprises a key slot, and the step of movingfurther comprises rotating the bolt to align the key with the key slotto allow the bolt to move through the bolt hole. After the tip isengaged with the stabilizer hole, the step of extending comprisesrotating the bolt to misalign the key and the key slot to prevent thebolt tip from moving away from the stabilizer hole.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1a shows a handle clamp for an exothermic mold according to anembodiment of the disclosure;

FIG. 1b shows an exploded view of the embodiment of FIG. 1 a;

FIG. 1c is a detailed view of a portion of the embodiment of FIG. 1ashowing different selected orientations of a bracket;

FIG. 2a is a perspective view of a handle clamp according to anembodiment of the disclosure in relation to an exothermic mold;

FIG. 2b shows another perspective view of the embodiment of FIG. 2a withthe handle clamp connected with the mold;

FIG. 3a shows a perspective view of the mold in a closed configurationaccording to the embodiment of FIG. 2 a;

FIG. 3b shows a perspective view of the mold in an open configurationaccording to the embodiment of FIG. 2 a;

FIG. 4 shows a partial cutaway view of the mold according to theembodiment of FIG. 2 a;

FIG. 5a shows a handle clamp according to another embodiment of thedisclosure in relation to an exothermic mold;

FIG. 5b shows a perspective view of the mold according to the embodimentof FIG. 5 a;

FIG. 5c shows a partial cutaway view of the mold according to theembodiment of FIG. 5 a;

FIG. 6a shows a perspective and partial cut away view of a bracket andspring-driven bolt according to another embodiment of the disclosure;

FIG. 6b shows an exploded view of the embodiment of FIG. 6 a;

FIG. 7a is a perspective view of the embodiment of FIG. 6a with thespring-driven bolt engaged with a section of an exothermic mold;

FIG. 7b is a perspective view of the embodiment of FIG. 6a with thespring-driven bolt disengaged from the section of the exothermic mold;

FIGS. 8a and 8b are perspective views of a bracket and spring-drivenbolt according to another embodiment of the disclosure;

FIG. 9 shows an exploded view of a spring-driven bolt and bracketaccording to another embodiment of the disclosure;

FIG. 10 shows an exploded view of a spring-driven bolt and bracketaccording to another embodiment of the disclosure; and

FIG. 11 shows an exploded view of a spring-driven bolt and bracketaccording to another embodiment of the disclosure.

DETAILED DESCRIPTION

FIG. 1a shows a handle for an exothermic welding mold 100. The handle100 includes insulated grips 102 connected with clamping arms 106. Alocking mechanism 104 is provided between the grips 102. As will bedescribed below, when the grips are squeezed together, arms 106 exert aclosing force on mold sections closing the mold cavity around conductorsor other objects that are to be welded together. The locking mechanism104 holds the handle in a clamped configuration. To open the mold, aninstaller disengages the locking mechanism 104 and pulls apart the gripsaway from one another, separating the arms 106 and opening the moldcavity.

Arms 106 bend 90 degrees to form legs 107. Rods 108 extent away from thesurface of legs 107. Brackets 110 are disposed on two of the rods 108.Brackets 110 can rotate around rods 108 and can be removably fixed inone of a plurality of angular positions about the rods, as will bedescribed below. According to one embodiment of the disclosure, brackets110 are “L” shaped with one side of the L having a hole through whichrod 108 extends. On the other side of the L, a threaded hole is providedand a thumb bolt 112 is engaged with the threaded hole. Other shapes ofbracket may be used, depending on the configuration of mold sections tobe held by the handle clamp.

The embodiment shown in FIG. 1a has brackets 110 disposed on the twoposts 108 nearest the 90 degree bend in arms 106. According to otherembodiments, to accommodate molds of different configurations, brackets110 are disposed on only one of these posts or on any combination of twoor more posts 108. Also, greater or fewer number of posts than the fourshown in FIG. 1a may be used to accommodate different configurations ofmolds.

FIG. 1b shows an exploded view of handle 100. Rods 108 fit through holesin one side of brackets 110. Coil springs 116 fit over rods 108 and restagainst the surface of brackets 110. Retaining rings 114 fit over rods108 above the springs 116 and engage with notches 115 that extend aroundthe circumference of the rods 108. The distance between the notch 115where the ring 114 is engaged and surface of leg 107 is selected so thatthe spring 116 is compressed between the retaining ring 114 and thesurface of bracket 110. Force exerted by the compressed spring 116presses the bracket 110 toward the surface of the leg 107. Pegs 118 aredisposed in holes in legs 107 near rods 108.

Pegs 118 are positioned to engage with one of a plurality of holes 120on brackets 110. The force of spring 116 presses bracket 110 towardsurface of leg 107, keeping peg 118 engaged with a selected one of theholes 120. This engagement locks bracket 110 into a selected angularorientation about rod 108. To change the angular orientation of abracket, the bracket 110 is rotated about the rod 108 so that the edgeof hole 120 rides up the side of peg 118, compressing spring 116 anddisengaging hole 120 from peg 118. A sloped surface (not shown) at theedge of holes 120 or on peg 118 may be provided to facilitatedisengagement of the peg and hole. When bracket 110 is rotated so thatanother hole 120 is aligned with peg 118, peg 118 engages with thatother hole 120 and spring 116 presses the newly selected hole over peg118. Instead of pegs 118, convex protrusions may be provided on thesurface of legs 107 to engage with brackets 110. Also, instead of holes120 on brackets 107, concavities such as dimples may be provided on thesurface of brackets 107 facing leg 107 to engage with pegs 118 or convexprotrusions on legs 107. Such concavities and/or convex protrusions canbe created by stamping. Also, instead of coil springs 116 shown in FIG.1 b, spring washers may be provided between rings 114 and brackets 110.

FIG. 1c shows bracket 110 in an orientation where thumb bolt 112 isperpendicular with leg 107. In this configuration, handle 100 is adaptedto connect with a mold that separated along a vertical plane like theone shown in FIGS. 2a -4, as will be described below. According to oneembodiment, when brackets 110 are rotated so that thumb bolts 112 areparallel with legs 107 and engaged, as shown in the phantom image ofFIG. 1 c, the handle 100 is adapted to connect with a mold thatseparates along a horizontal plane, like the one shown in FIGS. 5a -c,as will be described below.

Instead of springs 116 positioned between retaining rings 114 andbrackets 110, other mechanisms to apply a force on the brackets 110 canbe used, for example, spring washers, elastomeric washers, magneticinserts, and the like can be used. Also, instead of pegs or convexprotrusions extending from the surface of legs 107 to engage holes 120on the bracket, the peg or convex protrusion can be located on thebracket to engage with a plurality of holes or concave features on theleg.

FIGS. 2a shows handle 100 in relation to a mold 150 with the moldclosed. FIG. 2b shows handle 100 connected with the mold 150 and withthe mold in the open configuration. FIGS. 3a and 3b show perspectiveviews of the mold 150 without the handle attached. The mold is formedfrom two sections 151 a and 151 b that separate along a vertical plane.A lid 158 is joined to the top edge of one of the sections 151 b by ahinge 156. The mold 150 includes engagement holes 152. The engagementholes 152 are shaped to allow rods 108 on the handle 100 to be inserted.Holes 152 are deep enough so that, when rods 108 are fully inserted, thesurface of the mold contacts retaining rings 114 disposed on rods 108.Channel 160 allows one or more conductors to be positioned in the moldcavity. According to one embodiment, the mold is used to splice togetherthe ends of two conductors. The conductors are inserted into either endof channel 160 on opposite sides of the mold so that they meet at a moldcavity 204. When a reaction mixture is ignited, as will be describedbelow, the resulting molten metal flows into the mold cavity 204,welding the conductor ends together. The mold sections are thenseparated, allowing the joined conductors to be removed from the moldand the mold reused.

Stabilizer holes 154 are provided on the sides of the mold sections 151a, b adjacent to the sides including holes 152. Stabilizer holes 154 areblind holes that are sized to provide clearance for the ends of thumbbolts 112 of handle 100. According to one embodiment, stabilizer holes154 are perpendicular to engagement holes 152. Each mold portion 151 a,b fits over rods 108 on respective ones of legs 107. When rods 108 arefully inserted into holes 152 and brackets 110 are positioned with thethumb bolts 112 perpendicular to legs 107 as shown in solid lines inFIG. 1 c, thumb bolts 112 are aligned with stabilizer holes 154. Themold 150 is fixed to the handle 100 by screwing the thumb bolts 112 intostabilizer holes 154 so that the ends of the thumb bolts 112 engage withholes 154. This engagement prevents the mold 100 from sliding along rods108. Because the holes 120 on brackets 110 are engaged with pegs 118,the installer does not need to hold bracket 110 in position, while atthe same time rotating the thumb bolt 112.

To form a weld, the installer installs the mold 150 on handle 100, asdescribed above. The installer pulls apart grips 102 of the handle,pulling legs 107 holding mold sections 151 a,b away from one another toopen the mold cavity, as shown in FIG. 2b . The installer positions oneor more conductors to be welded into channel 160 of the mold. Theinstaller closes the mold by squeezing the grips together and engagingthe locking mechanism 104 to hold the mold sections 151 a,b tightlytogether.

FIG. 4 shows a partial cutaway view of the mold 150 with the sectionspressed together and conductors 206 positioned in channel 160. Forclarity, handle 100 is not shown. Surrounding the portion of theconductors 206 where the weld will be formed is a mold cavity 204. Themold cavity 204 is shaped to form a weld with the required mechanicaland electrical characteristics. Above the mold cavity 204 is a reactantcavity 202. The installer positioned a steel disc 208 at the bottom ofreactant cavity 202 above mold cavity 204. The installer fills reactantcavity 202 with a charge of reactant mixture and closes lid 158. Theinstaller pours a small amount of starter powder through a hole in lid158. The installer ignites the starter powder that, in turn, ignites thereactant mixture. The resulting exothermic reaction creates liquidmetal, for example, liquid copper, in the reactant cavity 202. When thetemperature in the reactant cavity is high enough the steel disc 208melts, allowing the liquid metal to flow into the mold cavity 204. Theliquid metal wets the conductors and fills the mold cavity 204, forminga welded connection between the conductors. Once the liquid metal coolsand solidifies, the installer disengages the lock 104 and pulls apartthe grips 102 of handle 100, separating legs 107 and respective moldsections 151 a, b. This allows the mold 150 to be removed from thewelded conductors.

FIG. 5a shows handle 100 in relation to a different configuration ofmold 250 than the one shown in FIGS. 2a -4. As shown in FIG. 5b , mold250 is formed from two sections 251 a and 251 b that separate from oneanother along a horizontal plane. Holes 252 are shaped to receive rods108. Stabilizer holes 254 are provide on sides of the mold to receivethumb bolts 112. As shown in FIG. 5a , handle 100 engages the moldsections 251 a and 251 b with the with grips 102 arranged vertically sothat legs 107 are positioned horizontally. The configuration of brackets110 is shown by the phantom lines in FIG. 1 c. Rods 108 on one of thelegs 107 engage the lower section of the mold 251 a and rods of theother leg 107 engage the upper section 251 b.

To connect mold 250 with handle 100, brackets 110 are turned so thatthumb bolts 112 are pointed parallel to legs 107 (as shown in thephantom image of FIG. 1c ). A different selected hole 120 on the bracketengages with pin 118 to hold the bracket in place than the one in theconfiguration described with respect to mold 150 in FIGS. 2a -4. In thisconfiguration, when rods 108 are inserted into holes 252, brackets 110extend along the sides of the mold sections 251 a and 251 b. Theinstaller tightens bolts 112 to engage with stabilizer holes 254.Because this mold opens along a horizontal plane, it can accommodatedifferent configurations of conductors. For example, as shown in FIG. 5c, a “T” shaped configuration of welded conductors can be formed usingthis type of mold.

In a similar manner as described with regard to FIG. 4, conductors 306are positioned so that the portions to be welded together are held inmold cavity 304. The grips 102 of the handle 100 are squeezed togetherand the locking mechanism 104 is engaged, forcing the mold sections 251a, b together. A reactant mixture is placed in reactant chamber 302. Thereactant mixture is ignited, causing a chemical reaction that generatesmolten metal and melts steel disc 308. The molten metal flows into moldcavity 304, forming the welded joint. The grips 102 of the handle 100are pulled apart, separating the mold sections and allowing the mold tobe removed from the finished weld and reused.

Instead of using threaded thumb bolts 112 to engage stabilizer holes154, 254, retractable spring-driven bolts may be provided. FIG. 6a showsa perspective and partial cut away view of bracket 410 and spring-drivenbolt 412 according to a further embodiment of the disclosure. FIG. 6bshows an exploded view of the bracket 410 and spring-driven bolt 412.Spring-driven bolts 412 replace one or more of bolts 112 of the previousembodiments. Spring-driven bolts can be used with or without the angularpositioning mechanism formed by holes 120 and pegs 118 described abovewith regard to brackets 110.

As shown in FIGS. 6a and 6b , one portion of bracket 410 includes a holesized to fit onto rod 108 of handle 100 as well as holes 420 that engagewith pins 118 of extending from the legs 107 of handle 100 in the samemanner as bracket 110 as described with respect to previous embodiments.This arrangement allows bracket 410 to be removably positioned in anangular orientation suitable for fitting the handle onto a selected moldsection as discussed above.

Bracket 410 includes key hole 408. Key hole 408 has a round opening andone or more keying slots 409. Spring bolt 412 includes shaft 420 with around cross section that is sized to fit through the round portion ofkey hole 408 and one or more keys or protrusions 422 extending radiallyfrom the shaft. When keys 422 are aligned with slots 409, the keys fitthrough the slots. Thumb pull 418 is provided at a proximal end of bolt412. Thumb pull 418 includes bearing surface 428. At the distal end ofshaft 420 is a mold engaging tip 424. Located near the distal end ofshaft 420 is a groove 426 shaped to engage with retaining ring 416.

When assembled, shaft 420 extends through hole 408. Spring 414 isdisposed around shaft 420. Retaining ring 416 is fitted over the distalend of shaft 420 and engages with groove 426. Spring 414 is compressedbetween the distal surface of bracket 410 and retaining ring 416 so thatbolt 412 is biased in the distal direction toward the surface of a moldsection installed on the handle clamp. Instead of a retaining ring 416engaged with a groove 426 to engage spring 414, bolt 412 could bemachined or forged to provide a spring-engaging flange or threads couldbe provided and a spring-retaining nut could be threaded onto the bolt.

FIG. 7a shows a partial cross section of bracket 410 and spring-drivenbolt 412 engaging mold section 451. As described with respect toprevious embodiments, engagement of bolt 412 with stabilizer hole 452 onthe side of the mold section 451 prevents mold section 451 from slidingalong rod 108. When tip 424 is engaged with stabilizer hole 452, theinstaller rotates bolt 412 so that the proximal end of key 422 is turnedaway from slot 409. The length of key 422 along bolt 412 is selected sothat the proximal end of key 422 contacts the distal surface of bracket410 preventing bolt 412 from moving in the proximal direction andsecuring the handle to the mold section.

According to another embodiment, bracket engaging surface 428 on bolt412 contacts the proximal surface of bracket 410 when tip 424 isinserted into hole 452. According to another embodiment, tip 424contacts a bottom of hole 452 and is held against the bottom of the holeby the biasing force exerted by spring 414. According to theseembodiments the length of key 422 can be selected to allow the installerto pull the bolt in the proximal direction far enough to disengage thetip 424 from the stabilizer hole 452 without having to align the key 422with slot 409.

FIG. 7b shows spring bolt 412 disengaged from mold section 451. To movethe bolt 412 from the engaged configuration in FIG. 7a to the disengagedconfiguration of FIG. 7b the installer turns bolt 412 so that key 422 isaligned with key slot 409. The installer pulls the bolt 412 in theproximal direction, compressing spring 414 against the distal side ofbracket 410. Once key 422 is pulled through slot 409, the installerturns bolt 412 so that the key is not aligned with the slot. Theinstaller releases bolt 412. The bias applied by spring 414 moves thebolt distally so that the distal end of the key 422 rests against theproximal side of bracket 410 as is shown in FIG. 7b . Mold section 451can now be pulled away from the handle 100 along rod 108 with bolt 412held out of the way.

To install a new mold section onto the handle, the installer puts bolt412 in the disengaged position shown in FIG. 7b and configures theangular positions of brackets 410 about rods 108 to accommodate theconfiguration of the newly selected mold. Pins 118 engage withappropriate holes 420, as described with respect to FIG. 2a or 5 a.FIGS. 8a and 8b show bracket 410 positioned either parallel orperpendicular with leg 107. Because bolts 412 are held in the disengagedconfiguration, the bolts will not interfere with the insertion of rods108 into a new mold section. Also, because brackets 410 are fixed in aparallel or perpendicular configuration with respect to legs 107 ofhandle 100 by the engagement of pins 118 with holes 420, the installerdoes not need to hold brackets 410 in place while the new mold sectionis fitted over rods 108. For embodiments where the angular engagementmechanism formed by holes 420 and pegs 118 is not used, the installerholds brackets 410 at the proper orientation while installing the moldsection onto rods 108.

Once rods 108 are fully inserted into mold section 451, the installerturns bolt 412 so that key 422 aligns with slots 409 of key hole 408.Bias applied by spring 414 moves bolt 412 distally toward mold section451 so that tip 424 engages with stabilizer hole 452 of the new moldsection. This fixes mold section onto rod 108. The installer can thenfit conductors into the mold cavity and create the exothermic weld asdescribed with respect to previous embodiments.

According to another embodiment, the spring is arranged to bias the boltin a direction away from the mold surface. Instead of being compressedbetween a distal surface of the bracket and a retaining ring, the springis affixed to the surface of the bracket and the retaining ring and isextended under tension when the tip of the bolt is engaged with thestabilizer hole of the mold. In this embodiment the bolt is held in adisengaged position by the biasing force of the spring. To install amold section, the installer aligns the key with the key slot and pushesthe bolt toward the mold section, extending the spring. When the tip ofthe bolt engages the stabilizer hole, the installer turns the bolt sothat the key is not aligned with the key slot. The proximal end of thekey rests against the distal surface of the bracket. The length of thekey is selected so that the tip of the bolt remains engaged with thestabilizer hole. To remove the mold section, the installer rotates thebolt until the key aligns with the key slot, allowing the bolt toretract away from the mold section under the biasing force of thespring.

FIG. 9 shows an exploded view of alternative embodiment of aspring-driven bolt 512 and bracket 510. As with the embodiment describedwith respect to FIGS. 6a and 6b , bolt 512 fits through a key hole 508of bracket 510. Bolt 512 has a hole 518 through shaft 520. Pin 522 isinserted into hole 518 and fixed, for example, by welding. The ends ofpin 522 extend from shaft 520 to form key protrusions, as discussed inprevious embodiments. Bolt 512 is inserted into hole 508 of bracket 510.Spring 514 is fitted over shaft 520 on the distal side of bracket 510.Retaining ring 516 is fitted over the end of bolt 512 and engages withspring 514 to provide a biasing force urging bolt 512 in the distaldirection.

FIG. 10 shows a spring-driven bolt 612 and bracket 610 according to afurther embodiment of the disclosure. Bolt 612 includes a threadedportion 624 at its distal end. The threads are configured to engage withinternal threading of a stabilizer hole of a mold section such as hole154 of mold section 151a, as shown in FIG. 3a . According to thisembodiment, to engage a mold section with handle 100, the installerrotates bolt 612 until protrusions 622 align with slots 609. As with theprevious embodiments, spring 614 biases bolt 612 in the distal directionand into contact with a threaded stabilizer hole of a mold section. Theinstaller rotates bolt 612 so that threaded portion 624 threads into thestabilizer hole, thus securing the mold section to the handle 100. Toremove the mold section from the handle, the installer unscrews bolt 612from the hole, aligns protrusions 622 with slots 609, pulls the bolt 612proximally so that protrusions 622 pass through the slots 609 to theproximal side of bracket 610, and rotates the bolt again so that theprotrusions can rest against the proximal surface of the bracket underthe biasing force of the spring.

Alternatively, instead of providing threads at the distal tip of thebolt, threads 723 may be provided on the shaft 720 of the bolt 712proximal of the protrusions 722 as shown in FIG. 11. Hole 708 of thebracket 710 is threaded to engage with threads 723 on bolt 712. As withprevious embodiments, spring 714 is provided around shaft 720 and iscaptive between retaining ring 716 and distal surface of bracket 710.The spring provides a biasing force urging bolt 712 in the distaldirection. To affix a mold section to the handle, the installerpositions bolt 712 so that the protrusions 722 are held against theproximal side of the bracket 710 by the biasing force of spring 714,thus stability holding the bolt out of the way so that rods 108 may beinserted into the mold section. The installer rotates bolt 712 so thatprotrusions 722 pass through slots 709 and bolt 712 moves toward themold section under the bias force of spring 714. The distal end ofthreaded portion 723 of shaft 720 contacts the proximal side of threadedhole 708. The installer rotates bolt 712 so that the threads engage,thus securing the bolt into engagement with the mold section.

While illustrative embodiments of the disclosure have been described andillustrated above, it should be understood that these are exemplary ofthe disclosure and are not to be considered as limiting. Additions,deletions, substitutions, and other modifications can be made withoutdeparting from the spirit or scope of the disclosure. Accordingly, thedisclosure is not to be considered as limited by the foregoingdescription.

We claim:
 1. A handle clamp for an exothermic mold comprising: a pair ofgrips; a pair of legs connected with respective ones of the grips, thelegs arranged to move toward and away from one another in response tomotion of the grips; a plurality of engagement rods disposed on each ofthe legs, wherein the engagement rods on each leg are adapted to engagewith respective sections of an exothermic mold; one or more brackets,each bracket rotatably disposed on one of the rods; and a detentmechanism to releasably hold the bracket in a selected angular positionwith respect to the rod.
 2. The handle clamp of claim 1, wherein thedetent mechanism comprises a convex feature and a plurality of concavefeatures arranged radially about the engagement rod, the convex featuredisposed on the leg or the bracket and the concave features disposed onthe other of the leg or the bracket, the concave and convex featuresshaped to engage with one another and positioned so that when a selectedone of the concave features is engaged with the convex feature, thebracket is positioned in a respective one of a plurality of angularpositions about the rod.
 3. The handle clamp of claim 2, wherein thedetent mechanism further comprises a force applying member adapted toapply a force to hold the engaged convex and concave features againstone another.
 4. The handle clamp of claim 3, wherein the force applyingmember is one of a coil spring, a spring washer, an elastomeric washer,and a magnetic insert.
 5. The handle clamp of claim 2, wherein theconcave feature is a hole or dimple on the leg or bracket.
 6. The handleclamp of claim 2, wherein the convex feature is a pin extending from oneof the leg or bracket and the concave feature is a hole in the other ofthe leg or bracket.
 7. The handle clamp of claim 1 further comprising alocking mechanism, the locking mechanism releasably locking the grips ina closed position.
 8. The handle clamp of claim 1, further comprising abolt hole through the bracket and a bolt disposed in the bolt hole andmovable toward and away from a surface of the mold.
 9. The handle clampof claim 8, wherein the bolt and the bolt hole are in threadedengagement with one another.
 10. The handle clamp of claim 8, whereinthe bolt hole further comprises a key slot, wherein the bolt furthercomprises a key, wherein the bolt is rotatable in the hole, and wherein,when the key is aligned with the key slot, the bolt can slide throughthe bolt hole.
 11. The handle clamp of claim 10, wherein a proximal endof the key engages a distal surface of the bracket when a tip of thebolt engages with the mold section.
 12. The handle clamp of claim 8,wherein the bolt comprises a bolt-driving spring arranged to bias thebolt in a direction toward or away from the mold.
 13. The handle clampof claim 12, wherein the bolt-driving spring comprises a coil spring,wherein the bolt further comprises a spring retaining feature, andwherein the coils spring is disposed between a surface of the bracketand the spring retaining feature.
 14. The handle clamp of claim 8,wherein the bolt further comprises a threaded portion adapted forthreaded engagement with a threaded hole of the mold section.
 15. Thehandle clamp of claim 9, wherein the threaded portion of the bolt isprovided only on a proximal portion of the bolt.
 16. A method forforming a weld comprising the steps of: providing an exothermic moldformed from a plurality of mold sections wherein the mold sectionscomprise rod engaging holes, stabilizer holes, and a mold cavity;providing a handle clamp, the handle clamp comprising: a pair of grips;a pair of legs connected with respective ones of the grips, the legsarranged to move toward and away from one another in response to motionof the grips; a plurality of engagement rods disposed on each of thelegs, wherein the engagement rods on each leg are adapted to be insertedinto engaging holes of respective sections of the mold; one or morebrackets rotatably disposed on respective ones of the rods, wherein thebracket comprises a bolt hole; a bolt movably disposed in the bolt hole;and a detent mechanism to releasably hold the bracket in a selectedangular position with respect to the rod; positioning the bracket in theselected angular position; engaging the detent mechanism to hold thebracket in the selected angular position; fitting the engagement rodsinto the rod engagement holes of the mold sections; extending the boltthrough the bolt hole toward the mold section; engaging a tip of thebolt with a respective stabilizer hole of the mold section; positioningthe mold sections adjacent a structure to be welded; squeezing the gripsto press the mold sections together; activating an exothermic reactionin the mold to form the weld in the mold cavity; separating the grips toseparate the mold sections; and removing the weld from the mold cavity.17. The method of claim 16, wherein the bolt and bolt hole comprisemutually engaged threads and wherein the step of extending comprisesrotating the bolt.
 18. The method of claim 16, wherein the handle clampfurther comprises a spring connected with the bolt and wherein the stepof extending comprises biasing the bolt into engagement with the moldsection with a biasing force applied by the spring.
 19. The method ofclaim 18, wherein the bolt further comprises a key, wherein the bolthole further comprises a key slot, and wherein the step of movingfurther comprises rotating the bolt to align the key with the key slotto allow the bolt to move through the bolt hole.
 20. The method of claim19, further comprising, after the tip is engaged with the stabilizerhole, rotating the bolt to misalign the key and the key slot to preventthe bolt tip from moving away from the stabilizer hole.